1. Field of the Invention
This invention relates to a device for at least partial covering of one or more transparent panes by means of a material which can be rolled up, especially advantageously, but not exclusively, in the field of motor vehicles.
2. Description of Related Art
Currently, roofs of motor vehicles are being increasingly equipped with transparent or translucent panes. Generally, either a sliding roof system with a movable pane made of glass, or a fixed pane which directly forms a more or less large part of the head liner is provided.
Regardless of the respective embodiment, in practice, this type of more or less transparent pane is systematically used in combination with a darkening device which is suited to being extended parallel to the inside surface of the glass pane. Such a device is designed to prevent light rays which are penetrating through the glass pane from propagating in the interior of the vehicle. The goal is, of course, to limit the greenhouse effect within the motor vehicle on days with strong incident solar radiation.
Darkening devices known from the prior art include devices whose operation requires use of a fabric which can be rolled up. Expressed schematically, a more or less transparent shade fabric for displacement relative to a region to be darkened is mounted to be able to move between a holding position and an extended position. The whole is made such that the shade fabric, in the receiving position, is rolled onto a take-up tube which is attached at a distance from the region to be darkened and the shade fabric extends in the drawn position underneath the region to be darkened.
It can sometimes be advantageous for the shade fabric to be supported in the lengthwise direction and/or in the transverse direction in the region to be darkened. This applies especially when the pane has large dimensions in order to avoid any “hammock” phenomenon under the action of the inherent weight of the shade fabric, and in this way, to ensure the efficiency and the purely aesthetic appearance of the darkening device. However, this is also the case when the pane to be darkened has a significant curvature in order to follow the inside of the indicated pane in the best possible manner, and thus, to optimize the use of space within the vehicle.
Regardless of this, for execution of such lengthwise and/or transverse support, connecting to the shade fabric one or more relatively stiff transverse reinforcements which are able to slide between two guide rails which each are located on either side of the region to be darkened is known. The simple presence of the transverse reinforcements which are permanently joined to the shade fabric is sufficient to obtain the desired support in the transverse direction. And if this is combined with the use of guide rails which are shaped essentially parallel to the curvature of the pane to be darkened, this advantageously allows the desired support in the lengthwise direction to be obtained. It should be noted that due to the fact that the transverse reinforcements are permanently joined to the shade fabric, especially by means of coatings, they are able to slide together with it, on the one hand, in the region to be darkened, and on the other hand, to be taken up together with it around the take-up tube.
However, this type of darkening device has the disadvantage of being especially bulky in the receiving area of the shade fabric. The fact that the height of each of the transverse reinforcements is added to that of the shade fabric at the instant of take-up significantly increases the diameter of the whole in the receiving position. Ultimately, this is especially harmful for utilization of space in the motor vehicle, especially with reference to head room.